Alzheimer's disease (AD) is a major public health problem due to its increasing prevalence, long duration, caregiver burden and high financial cost of care. In Alzheimer's disease, the most characteristic neuropathological changes are the formation of neurofibrillary tangles and neuritic plaques characterized by the presence of bundles of paired helical filaments that accumulate in the degenerating neurites and neuronal cell bodies. Classic neuritic plaques have a central dense core of β-amyloid peptide surrounded by a corona of dystrophic neurites (Esiri M M et al., J Neurol Neurosurg Psychiatry (1998) 65:29-33). Although the protein composition of the paired helical filaments is ill-defined, a number of microtubule-associated proteins have been implicated in these lesions. So, it has been reported that in the brains affected by Alzheimer's disease, the levels of microtubule-associated protein 2 (MAP 2) are usually decreased [Adlard P A, Vickers J C; Acta Neuropathol (2002) 103: 377-383; Hsia A Y et al.; Proc Natl Acad Sci USA (1999) 96: 3228-3233].
Currently there is no treatment for Alzheimer's disease. Current efforts to develop an effective treatment for AD are based upon the finding that Alzheimer's disease patients suffer from marked deficits in cholinergic neurotransmitter system, resulting in a deficiency in acetylcholine concentration in the central nervous system. Treatment approaches include precursors for acetylcholine synthesis, cholinergic agonists, acetylcholine release enhancers and acetylcholinesterase (AChE) inhibitors. To date, the most effective approach has been the use of AChE-inhibitors, such as tacrine, donepezil, and rivastigmine.
Previous studies showed that AD pathogenesis is triggered by the accumulation and deposition of toxic β-amyloid peptide (Aβ) in the central nervous system [Callizot et al., J. Neurosc. Res. (2013) 91(5):706-16]. Herbal medications targeting the mechanisms underlying Aβ-accumulation might be an effective approach to preventing the disease. Parkinson's disease (PD) is the second most common neurodegenerative disorder in the United States. The predominant motor symptoms of PD including slow movement, resting tremor, rigidity and gait disturbance are caused by the loss of dopaminergic neurons in the substantia nigra (SN). Epidemiological studies suggest that the use of pesticides increases the risk of PD, possibly via reduced activity of complex I in the mitochondrial respiratory chain in the substantia nigra and result in the pathogenesis of PD. 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its derivative form (MPP+), a mitochondrial complex I inhibitor, has been widely used to produce toxin models of sporadic PD. This toxin is used to mimic in vitro PD [Visanji. et al., FASEB J. 2008; 22(7):2488-97].
Amyotrophic lateral sclerosis (ALS), also called Lou Gehrig's disease or classical motor neuron disease, is the most common form of motor neuron disease (MND), with both upper and lower motor neuron involvement. This form of the disease is characterized by weakness and wasting in the limbs. Muscle weakness and atrophy occur on both sides of the body. Affected individuals lose strength and the ability to move their arms and legs, and to hold the body upright. Other symptoms include spasticity, spasms, muscle cramps, and fasciculations. Speech can become slurred or nasal. When muscles of the diaphragm and chest wall fail to function properly, individuals lose the ability to breathe without mechanical support. Although the disease does not usually impair a person's mind or personality, several recent studies suggest that some people with ALS may develop cognitive problems involving word fluency, decision-making, and memory. Most individuals with ALS die from respiratory failure, usually within 3 to 5 years from the onset of symptoms. Complex pathophysiology of ALS presents many potential therapeutic targets. However, although a wide range of agents has been investigated, only Riluzole (Rilutek®), an inhibitor of glutamate release, has demonstrated consistent benefits, and is the only approved drug for the treatment of the disease.
But Riluzole's benefits are modest—it prolongs survival in ALS patients for several months (˜7%) with minimal effect on functional measures. At present, ALS remains a disease for which limited effective treatment options are available. There is clearly an unmet need for more beneficial agents acting through others mode of action: growth factors, ionic alterations, inflammation, mitochondrial alteration, apoptosis . . . .
Huperzine A, a sesquiterpene alkaloid, is isolated from the Chinese club moss Huperzia serrata also known as Lycopodium serratum. The plant contains mainly alkaloids, triterpenes, flavones, and phenolic acids. Four major structural classes of Lycopodium alkaloids have been described, including lycopodine, lycodine (to which huperzine A belongs), fawcettimines, and others.
Huperzine A and huperzine B are potent acetylcholinesterase inhibitors and a promising therapeutic approach in Alzheimer's disease. Huperzine A has been studied for potential use in treating Alzheimer disease and other CNS disorders [Xu et al., Acta Phamacol. Sin. (1999), 20:486-49; Wang et al., J Neural Transm 2009, 116: 457-465]. The results indicate that huperzine A is well-tolerated and beneficial for Alzheimer's disease patients, particularly when administered at a daily dose of 300-500 μg [Wang et al. 2009, already cited; Xing et al. Evidence-Based Complementary and Alternative Medicine, volume 2014, Article ID 363985, 10 pages]. In addition to its acetylcholinesterase inhibitory effect, huperzine A possesses different other pharmacological effects. These noncholinergic roles, for instance the antagonistic effect on NMDA receptor, the protection of neuronal cells against 62-amyloid, free radicals and hypoxia-ischemia-induced injury, could be important in AD treatment. Growing studies have indicated that a range of Chinese herbs or herbal extracts such as green tea polyphenols or catechins, panax ginseng and ginsenoside, ginkgo biloba and EGb 761, polygonum, triptolide from tripterygium wilfordii hook, polysaccharides from the flowers of nerium indicum, oil from ganoderma lucidum spores, huperzine and stepholidine are able to attenuate degeneration of dopamine neurons and symptoms caused by the neurotoxins 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and 6-hydroxydopamine (6-OHDA) in vitro and in vivo conditions. In addition, accumulating data have suggested that Chinese herbs or herbal extracts may promote neuronal survival and neurite growth, and facilitate functional recovery of brain injuries [Liang-Wei Cheng et al. in CNS & Neurological Disorders—Drug Targets (Formerly Current Drug Targets—CNS & Neurological Disorders), 2007, 6(4), 273-281].
Animal and clinical studies showed that huperzine A, when administered orally, is absorbed rapidly, distributed throughout the body and eliminated at a moderate rate, and that huperzine A has a lower toxicity compared to other drugs such as tacrine which has significant hepatotoxic potential.
Huperzine B (HupB), the minor alkaloid in the plant Huperzia serrata and a structural sibling of huperzine A, is less potent and selective in the inhibition of AChE than HupA. However, it possesses a higher therapeutic index than huperzine A that is in agreement with its longer duration of action. In behavioural studies, HupB improved memory retention and memory retrieval in adult and aged mice, and reversed the disruption of memory retention induced by scopolamine, sodium nitrite, electroconvulsive shock, and cycloheximide in mice [Zhu X. D. et al., Acta Pharmacol. Sin. (1988) 9(6): 492-497]. Recent studies also revealed new 16-substituted derivatives of HupB that exert neuroprotective effects by attenuating hydrogen peroxide-induced neurotoxicity [Shi et al., Acta Pharmacologica Sinica (2009) 30: 1195-1203].
There are a number of synthetic huperzine A analogs. Huprine X for example is a fusion product that combines the carbobicyclic substructure of huperzine A with the 4-aminoquinoline substructure of tacrine [Badia A et al, Bioorg Med Chem 1998, 6:427-440]. Another synthetic analog is ZT-1, which is a prodrug that, in the body, is progressively hydrolysed into huperzine A [Li et al, Biomed Chromatogr 2008, 22:354-360]. These “hybrid” products are of interest because they may be effective at lower doses and, therefore, cause fewer side effects.
Hydroxycinnamic acids are phenolic phytochemicals present in fruits, vegetables, and coffee. This group of polyphenols includes caffeic acid, ferulic acid, chlorogenic acid, isoferulic acid and coumaric acid, which are known to exert beneficial effects linked to their antioxidant activity.
Ferulic acid, also named as 4-hydroxy-3-methoxy cinnamic acid, is a phenol acid widely found in a variety of plants. Ferulic acid has a wide range of pharmacological effects such as anti-inflammatory effect, antibacterial effect, antioxidant effect and antitumor effect. Among its various benefits, much interest has been focused on the suppressive effect of ferulic acid on Alzheimer's disease [Nakamura, S. et al., Geriat. Med. 46, 1511-1519 (2008)].
Caffeic acid, a hydroxycinnamic acid derivative has antioxidant, anti-inflammatory, analgesic and immunomodulatory effects. Literature also reports the neuroprotective effects of caffeic acid [Anwar J. et al., Pharmacol Biochem Behav; 2:386-394 (2012), Jeong C H et al., Chin Med, 6:25 (2011)].
Although huperzines as well as hydroxycinnamic acids have been used separately in clinical trials for treatment of neurodegenerative diseases, no studies have evaluated the effect of compositions combining huperzine and hydroxycinnamic acids on Alzheimer's disease.
WO2011/132157 discloses sustained-release formulations comprising huperzine A and methods utilising said formulations for treating a medical condition such as Alzheimer's disease.
EP2343065 A1 discloses a composition comprising a combination of ferulic acid and matrine compounds and its therapeutic use for treating various diseases such as Alzheimer's disease.
WO2008/108825 discloses pharmaceutical compositions comprising a neuroprotective amount of a compound selected in particular from members of the group consisting of para carnosic acid, para L-dopa, para caffeic acid or a pharmaceutically acceptable prodrug, salt or solvate thereof.
Thus, none of the above mentioned prior arts disclose a specific combination of huperzine and hydroxycinnamic acids.
In this context, the inventors have shown for the first time that huperzine and hydroxycinnamic acids have synergistic effects when used in combination for the treatment of Alzheimer's disease. They investigated the neuroprotective effect of a plant extract of Huperzia serrata on rat primary cortical neurons injured with glutamate as in vitro model of AD. In light of the obtained results and an analytical analysis of the chemical profile of the extract, they identified three compounds potentially involved in the neuroprotective effect: huperzine A, caffeic acid and ferulic acid. The synergistic effect of these compounds was also investigated.
The effect of said compounds was further investigated in a second in vitro model of AD which is β-amyloid peptide injured primary cortical neurons.
Therefore one object of the present invention is to provide a combination composition for treatment of Alzheimer's disease and other CNS disorders and a preparation method thereof.
According to the present invention, a combination composition is provided comprising as active components, in synergistically effective amounts (i) a huperzine of natural or synthetic origin or a plant extract containing huperzine, and (ii) at least two compounds selected from the group consisting of hydroxycinnamic acids, anthoxanthins and anthocyanins of natural or synthetic origin, mixtures thereof and a plant extract containing same.
The huperzine is selected from the group consisting of huperzine A, huperzine B, analogs thereof and mixtures thereof. According to the invention, the composition may contain huperzine A alone or huperzine B alone or an analog thereof alone or a combination of two or more of huperzine A, huperzine B and analogs.
The active compounds may be used as such or under the form of physiologically acceptable salts.
The active components may be naturally occurring or synthetic. Non-naturally occurring active agents may suitably be prepared by modification of side groups and/or side atoms of naturally occurring compounds, as known in the art.
Extracts of plant in particular Huperzia serrata extract may also be used. Thus, according to the present invention, said combination composition may be an aqueous or an organic mixture of said active components or a plant extract. Such extracts may be prepared by any technics known in the art.
According to a preferred embodiment of the present invention, the at least two compounds (ii) are two hydroxcinnamic acids of natural or synthetic origin. According to the Invention, the hydroxycinnamic acids are selected from the group comprising or consisting of α-cyano-4-hydroxycinnamic acid, caffeic acid, cichoric acid, cinnamic acid, chlorogenic acid, diferulic acids, coumaric acid, coumarin, ferulic acid, sinapinic acid.
According to a most preferred embodiment, the hydroxycinnamic acids are caffeic acid and ferulic acid. Advantageously, the huperzine, in particular huperzine A, the caffeic acid and the ferulic acid may be used in different ratios, e.g., at a molar ratio huperzine/caffeic acid/ferulic acid; for example it may be comprised between from 0.01/0.5/10 to 0.1/5/1000, preferentially between from 0.01/0.5/10 to 0.1/0.5/1000, advantageously equal to 0.01/0.5/100; another possible ratio is 0.01/50/100 or 0.01/5/100. It will be understood that the amount of the drug actually administered will be determined by a physician, in the light of the relevant circumstances including the condition or conditions to be treated, the exact composition to be administered, the age, weight, and response of the individual patient, the severity of the patient's symptoms, and the chosen route of administration. Therefore, the above dosage ranges are intended to provide general guidance and support for the teachings herein, but are not intended to limit the scope of the invention. An advantage of the invention is that each compound may be used at low doses in a combination therapy, while producing, in combination, a substantial clinical benefit to the subject. The combination therapy may indeed be effective at doses where the compounds have individually low or no effect. Accordingly, a particular advantage of the invention lies in the ability to use sub-optimal doses of each compound, i.e., doses which are lower than therapeutic doses usually prescribed, preferably ½ of therapeutic doses, more preferably ⅓, ¼, ⅕, or even more preferably 1/10 of therapeutic doses. In particular examples, doses as low as 1/20, 1/30, 1/50, 1/100, or even lower, of therapeutic doses are used. At such sub-therapeutic dosages, the compounds would exhibit no side effect, while the combination(s) according to the invention are fully effective for treatment of Alzheimer's disease and other CNS disorders.
According to another object of the present invention, there is provided a combination composition such as described before for its use in preventing, inhibiting, retarding or treating neuronal degeneration in a subject suffering from a neurodegenerative disease or condition.
More particularly the invention provides a combination composition for its use in preventing inhibiting, retarding or treating a subject suffering from a disease or condition selected from the group consisting of: Alzheimer's disease (AD), senile dementia of AD type (SDAT), Parkinson's disease, Lewis body dementia, vascular dementia, autism, myasthenia gravis, Lambert Eaton disease, mild cognitive impairment (MCI), age-associated memory impairment (AAMI) and problem associated with ageing, (i) non-cognitive neurodegeneration, (ii) non-cognitive neuromuscular degeneration, (iii) motor-sensory neurodegeneration, or (iv) receptor dysfunction or loss in the absence of cognitive, neural and neuromuscular impairment, in a human or non-human animal subject suffering from, or susceptible to, any of Parkinson's disease, postencephalitic Parkinsonism, depression, schizophrenia, muscular dystrophy including facioscapulohumeral muscular dystrophy (FSH), Duchenne muscular dystrophy, Becker muscular dystrophy and Bruce's muscular dystrophy, Fuchs' dystrophy, myotonic dystrophy, corneal dystrophy, reflex sympathetic dystrophy syndrome (RSDSA), neurovascular dystrophy, Huntington's disease, motor neurone diseases including amyotrophic lateral sclerosis (ALS), multiple sclerosis, postural hypotension, traumatic neurodegeneration, Batten's disease, Cockayne syndrome, Down syndrome, corticobasal ganglionic degeneration, multiple system atrophy, cerebral atrophy, olivopontocerebellar atrophy, dentatorubral atrophy, pallidoluysian atrophy, spinobulbar atrophy, optic neuritis, subacute sclerosing panencephalitis (SSPE), attention deficit disorder, post-viral encephalitis, post-poliomyelitis syndrome, Fahr's syndrome, Joubert syndrome, Guillain-Barre syndrome, lissencephaly, Moyamoya disease, neuronal migration disorders, autistic syndrome, polyglutamine disease, Niemann-Pick disease, progressive multifocal leukoencephalopathy, pseudotumor cerebri, Refsum disease, Zellweger syndrome, supranuclear palsy, Friedreich's ataxia, spinocerebellar ataxia type 2, Rhett syndrome, Shy-Drager syndrome, tuberous sclerosis, Pick's disease, chronic fatigue syndrome, neuropathies including hereditary neuropathy, diabetic neuropathy and anti-mitotic neuropathy, prion-based neurodegeneration, including Creutzfeldt-Jakob disease (OD), variant CJD, new variant CJD, bovine spongiform encephalopathy (BSE), GSS, FFI, kuru and Alper's syndrome, Joseph's disease, acute disseminated encephalomyelitis, arachnoiditis, vascular lesions of the central nervous system, loss of extremity neuronal function, Charcot-Marie-Tooth disease, susceptibility to heart failure, asthma, and macular degeneration. The composition is particularly useful for the treatment and prevention of Alzheimer disease.
According to still another object of the present invention, there is provided a method for preventing, inhibiting, retarding or treating neuronal degeneration in a subject in need thereof, wherein the method comprises administering an effective amount of the composition according to the invention to said subject.
As described herein, the combination compositions according to the present invention may be prepared as pharmaceutical compositions, especially pharmaceutical compositions useful for the treatment of Alzheimer's disease. Such compositions may comprise the active compounds (i) and (ii) as defined above together with a pharmaceutically acceptable excipient.
According to a further aspect of the present invention, the combination composition may be prepared as neutraceutical compositions comprising the active compounds (i) and (ii) as defined above together with a nutraceutically acceptable excipient.
The combination composition according to the present invention can be formulated for oral administration, topical administration, transdermal administration, parenteral administration and combinations thereof.
Suitable forms for oral administration include tablets, compressed or coated pills, dragées, sachets, troches, granulates, hard or soft gelatin capsules, sublingual tablets, syrups, solutions, and suspensions, aerosols; for parenteral administration the invention provides ampoules or vials that include an aqueous or non-aqueous solution or emulsion; for rectal administration there are provided suppositories with hydrophilic or hydrophobic vehicles; and for topical application as ointments and transdermal delivery there are provided suitable delivery systems as known in the art for example patches.
The preferred dosages of the active ingredients in the above compositions will be defined by the one skilled in the art on the basis of his general knowledge. Said dosages may be taken daily in one or several outlet.
In accordance with the present invention, the composition may be formulated for immediate release, extended release or timed release.
According to a further aspect of the invention, the combination composition may be for simultaneous, separate or sequential use in treating or preventing a neurodegenerative disease or condition.
The invention further provides an extract of Huperzia serrata comprising huperzine A/caffeic acid/ferulic acid at a molar ratio at a molar ratio comprised between from 1/0.1/0.1 to 1/0.4/0.6, preferentially at a molar ratio of 1/0.1/0.5. Such an extract has good therapeutic effect and is suitable for simultaneous, separate or sequential use in treating or preventing a neurodegenerative disease or condition.